The invention relates to seed pellets each containing at least one grain of seed and an organic substrate.
In Swiss patent specification No. 561 021 there was revealed a seed preparation (compound) produced by mixing 20 kg of poor-grade grass, so-called mulch, and 1 kg of crude cellulose flakes, and drying the mixture at a temperature of about 140.degree. C. until the residual water content is only 15% by weight. The following substances are then added to this premixture, the percentages given representing % by weight, relative to the dried grass.
1.5% of 1,4 butanediol as hydrophilic constituent PA1 2% of seed PA1 0.25% of sodium alginate PA1 0.25% of polyacrylic amide PA1 0.25% of octylphenyl octoglycol ether PA1 0.25% of fungicide PA1 0.5% of nutrient salts
This mixture can be compressed to moulded bodies, so-called pellets wherein the sodium alginate and polyacrylic amide act as binding agents.
According to Swiss patent specification No. 561 021 such pellets are provided with grass seeds and, in practice, with clover seed (leguminosa) too. These pellets, however, are not suitable for seeds which require relatively much water, and/or are sown in extremely dry areas, such as the seed of dry rice and of many other cultivated plants or forest seeds. The dried grass, of which the percentage by weight in the pellets is of the order of 90%, can give off only about one-third of this water content of about 15% by weight which exists therein, i.e., only about 5% of the weight of the dried grass. Furthermore, the pellets known lose relatively much water to the environment in a dry environment. A further disadvantage of the seed pellets according to Swiss patent specification No. 561 021 resides in the fact that the dried grass particles, seeds and other pellet constituents pressed to form pellets are held together only relatively loosely so that they break readily during transport and on sowing, and lose material through abrasion.